The present embodiment relates to an electrical switchgear and, more particularly, to an enclosure for a switchgear and a ventilation system therefor.
With reference to FIG. 1, a conventional switchgear is shown, generally indicated at 10. The switchgear includes an enclosure 12 that includes at least one circuit breaker compartment 14 housing a conventional circuit breaker 15, a main bus compartment 16 adjacent to the circuit breaker compartment 14 and a cable compartment 18 adjacent to the main bus compartment 16 and to the circuit breaker compartment 14.
Venting of the enclosure occurs as natural convective airflow occurs through openings 20 in doors 22 of the circuit breaker compartment 14 through openings 24 in the top of the circuit breaker compartment 14, through opening 24′ in the top of the main bus compartment 16, and through louvered vent boxes 25. The conventional louvered flaps 27 of the vent boxes 25 however resist natural ventilation of the hot air.
It is difficult to vent and cool the buses 26 in the main bus compartment 16 since the busses 26 are aligned along a common axis X in a vertically stacked arrangement, causing hot air from the lower buses to heat up the upper buses. For example, bus 26′ will receive heat from the buses 26″ and 26′″ and bus 26″ will receive heat from bus 26″. Furthermore, although airflow may be efficient over buses 26′ and 26′″, it is not efficient over middle bus 26″ and hot air accumulation from the bus 26″ towards the top of the main bus compartment 16 results in less efficient ventilation for the bus 26″. Also, the cable compartment 18 has no vent opening to atmosphere.
Thus, there is a need to provide an improved switchgear enclosure that ensures proper ventilation of the circuit breaker compartment, a main bus compartment, and a cable compartment and to ensure efficient airflow over all buses.